May Flowers or May Showers?

Submitted by Shawn Crowe on Tue, 04/30/2013 - 1:50pm

The outlook for April worked out great. Highs in the 50s and 60s were common most days, and it turned out to be a wet month. Let me give a few thoughts about May. They say April showers bring May flowers, but for 2013 we’re probably just looking at more showers.

NOAA - National Centers for Environmental Prediction

Notice the sprawling upper level lows south of Alaska and across eastern Canada. This is called an "omega block" because of it's resemblance to the Greek omega character. This pattern will keep the Ohio Valley in northwesterly flow, and will prevent truly warm air to our south along the Gulf Coast from moving northward. The result should be a generally cool and wet May.

The weather for Derby weekend is looking iffy. On one hand you’ve got the GFS model which tries to hold a cut-off low out in Missouri and that would mean showers and storms staying just west of I-65 through Saturday. On the other hand you’ve got the ECMWF model bringing the low closer to Kentucky and the resulting rain moves into our area for Saturday. Both models are pretty similar, but in this case 100 miles is going to make the difference. It’s going to be a very tough forecast. Will the Kentucky Derby run in the rain or on a dry track? That is anyone’s guess. These pesky cut-off low pressure systems spin over an area for days on end and really wreak havoc with everything. One thing that’s pretty sure is that the weather will be unsettled this weekend with chances for rain through at least Monday.

As we head into mid-May, signs are pointing to more upper level blocking occurring in Canada. Unfortunately this means a continuation of northerly flow and cooler air. It looks to me like the weather we’ve seen in April will carry us into most of May as well. We normally start seeing a big warm-up in May with days in the 80s being common. I don’t think that’s going to be the norm this year. I think a generally cool and wet pattern is going to rule the month. May is the wettest month in central Kentucky. We average 5.26" of rain for the month. I think this year we'll easily reach and perhaps pass that total. There are signs that we could see low temperatures into the low 40s even at mid-month and many days with highs in the 50s and 60s which is well below average. Those who enjoy outdoor activities won’t be very excited about that forecast, but agricultural interests should be happy for frequent rainfall and mild temperatures. This may turn out to be a pretty good growing season. The bottom line is that we’re going to have to hang onto the jackets a little longer than usual this year.